Skip to content

Skip ChannelManager persistence after monitor update completion #4424

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Draft
joostjager wants to merge 2 commits into
base: main
Choose a base branch
from
Draft

Skip ChannelManager persistence after monitor update completion #4424

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
1683dbb
Return NotifyOption from process_pending_monitor_events
joostjager Feb 25, 2026
b0ec5eb
Skip ChannelManager persistence for message-only monitor completions
joostjager Feb 25, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
104 changes: 69 additions & 35 deletions lightning/src/ln/channelmanager.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -3372,8 +3372,12 @@ macro_rules! process_events_body {

// TODO: This behavior should be documented. It's unintuitive that we query
// ChannelMonitors when clearing other events.
if $self.process_pending_monitor_events() {
result = NotifyOption::DoPersist;
match $self.process_pending_monitor_events() {
NotifyOption::DoPersist => result = NotifyOption::DoPersist,
NotifyOption::SkipPersistHandleEvents
if result == NotifyOption::SkipPersistNoEvents =>
result = NotifyOption::SkipPersistHandleEvents,
_ => {},
}
}

Expand Down Expand Up @@ -10165,13 +10169,14 @@ This indicates a bug inside LDK. Please report this error at https://github.com/
let logger = WithChannelContext::from(&self.logger, &chan.context, None);
let update_completed = self.handle_monitor_update_res(update_res, logger);
if update_completed {
Some(self.try_resume_channel_post_monitor_update(
let (data, _needs_persist) = self.try_resume_channel_post_monitor_update(
in_flight_monitor_updates,
monitor_update_blocked_actions,
pending_msg_events,
is_connected,
chan,
))
);
Some(data)
} else {
None
}
Expand Down Expand Up @@ -10231,13 +10236,14 @@ This indicates a bug inside LDK. Please report this error at https://github.com/
);

let completion_data = if all_updates_complete {
Some(self.try_resume_channel_post_monitor_update(
let (data, _needs_persist) = self.try_resume_channel_post_monitor_update(
in_flight_monitor_updates,
monitor_update_blocked_actions,
pending_msg_events,
is_connected,
chan,
))
);
Some(data)
} else {
None
};
Expand All @@ -10262,7 +10268,7 @@ This indicates a bug inside LDK. Please report this error at https://github.com/
>,
pending_msg_events: &mut Vec<MessageSendEvent>, is_connected: bool,
chan: &mut FundedChannel<SP>,
) -> PostMonitorUpdateChanResume {
) -> (PostMonitorUpdateChanResume, bool) {
let chan_id = chan.context.channel_id();
let outbound_alias = chan.context.outbound_scid_alias();
let counterparty_node_id = chan.context.get_counterparty_node_id();
Expand All @@ -10280,7 +10286,8 @@ This indicates a bug inside LDK. Please report this error at https://github.com/

if chan.blocked_monitor_updates_pending() != 0 {
log_debug!(logger, "Channel has blocked monitor updates, completing update actions but leaving channel blocked");
PostMonitorUpdateChanResume::Blocked { update_actions }
let needs_persist = !update_actions.is_empty();
(PostMonitorUpdateChanResume::Blocked { update_actions }, needs_persist)
} else {
log_debug!(logger, "Channel is open and awaiting update, resuming it");
let updates = chan.monitor_updating_restored(
Expand Down Expand Up @@ -10311,6 +10318,11 @@ This indicates a bug inside LDK. Please report this error at https://github.com/
None
};

// Checked before handle_channel_resumption moves these fields.
let has_state_changes = updates.funding_broadcastable.is_some()
|| updates.channel_ready.is_some()
|| updates.announcement_sigs.is_some();

let (htlc_forwards, decode_update_add_htlcs) = self.handle_channel_resumption(
pending_msg_events,
chan,
Expand All @@ -10333,19 +10345,32 @@ This indicates a bug inside LDK. Please report this error at https://github.com/
let unbroadcasted_batch_funding_txid =
chan.context.unbroadcasted_batch_funding_txid(&chan.funding);

PostMonitorUpdateChanResume::Unblocked {
channel_id: chan_id,
counterparty_node_id,
funding_txo: chan.funding_outpoint(),
user_channel_id: chan.context.get_user_id(),
unbroadcasted_batch_funding_txid,
update_actions,
htlc_forwards,
decode_update_add_htlcs,
finalized_claimed_htlcs: updates.finalized_claimed_htlcs,
failed_htlcs: updates.failed_htlcs,
committed_outbound_htlc_sources: updates.committed_outbound_htlc_sources,
}
// Queuing outbound messages (commitment_update, raa) alone does
// not require ChannelManager persistence.
let needs_persist = has_state_changes
|| !updates.finalized_claimed_htlcs.is_empty()
|| !updates.failed_htlcs.is_empty()
|| !update_actions.is_empty()
|| unbroadcasted_batch_funding_txid.is_some()
|| !htlc_forwards.is_empty()
|| decode_update_add_htlcs.is_some();

(
PostMonitorUpdateChanResume::Unblocked {
channel_id: chan_id,
counterparty_node_id,
funding_txo: chan.funding_outpoint(),
user_channel_id: chan.context.get_user_id(),
unbroadcasted_batch_funding_txid,
update_actions,
htlc_forwards,
decode_update_add_htlcs,
finalized_claimed_htlcs: updates.finalized_claimed_htlcs,
failed_htlcs: updates.failed_htlcs,
committed_outbound_htlc_sources: updates.committed_outbound_htlc_sources,
},
needs_persist,
)
}
}

Expand Down Expand Up @@ -10614,13 +10639,14 @@ This indicates a bug inside LDK. Please report this error at https://github.com/
}

#[rustfmt::skip]
fn channel_monitor_updated(&self, channel_id: &ChannelId, highest_applied_update_id: Option<u64>, counterparty_node_id: &PublicKey) {
fn channel_monitor_updated(&self, channel_id: &ChannelId, highest_applied_update_id: Option<u64>, counterparty_node_id: &PublicKey) -> bool {
debug_assert!(self.total_consistency_lock.try_write().is_err()); // Caller holds read lock

let per_peer_state = self.per_peer_state.read().unwrap();
let mut peer_state_lock;
let peer_state_mutex_opt = per_peer_state.get(counterparty_node_id);
if peer_state_mutex_opt.is_none() { return }
// Peer is gone; conservatively request persistence.
if peer_state_mutex_opt.is_none() { return true }
peer_state_lock = peer_state_mutex_opt.unwrap().lock().unwrap();
let peer_state = &mut *peer_state_lock;

Expand Down Expand Up @@ -10652,15 +10678,15 @@ This indicates a bug inside LDK. Please report this error at https://github.com/
} else { 0 };

if remaining_in_flight != 0 {
return;
return false;
}

if let Some(chan) = peer_state.channel_by_id
.get_mut(channel_id)
.and_then(Channel::as_funded_mut)
{
if chan.is_awaiting_monitor_update() {
let completion_data = self.try_resume_channel_post_monitor_update(
let (completion_data, needs_persist) = self.try_resume_channel_post_monitor_update(
&mut peer_state.in_flight_monitor_updates,
&mut peer_state.monitor_update_blocked_actions,
&mut peer_state.pending_msg_events,
Expand All @@ -10675,16 +10701,20 @@ This indicates a bug inside LDK. Please report this error at https://github.com/

self.handle_post_monitor_update_chan_resume(completion_data);
self.handle_holding_cell_free_result(holding_cell_res);
needs_persist
} else {
log_trace!(logger, "Channel is open but not awaiting update");
false
}
} else {
let update_actions = peer_state.monitor_update_blocked_actions
.remove(channel_id).unwrap_or(Vec::new());
let needs_persist = !update_actions.is_empty();
log_trace!(logger, "Channel is closed, applying {} post-update actions", update_actions.len());
mem::drop(peer_state_lock);
mem::drop(per_peer_state);
self.handle_monitor_update_completion_actions(update_actions);
needs_persist
}
}

Expand Down Expand Up @@ -13013,13 +13043,17 @@ This indicates a bug inside LDK. Please report this error at https://github.com/
Ok(())
}

/// Process pending events from the [`chain::Watch`], returning whether any events were processed.
fn process_pending_monitor_events(&self) -> bool {
/// Process pending events from the [`chain::Watch`], returning the appropriate
/// [`NotifyOption`] for persistence and event handling.
fn process_pending_monitor_events(&self) -> NotifyOption {
debug_assert!(self.total_consistency_lock.try_write().is_err()); // Caller holds read lock

let mut failed_channels: Vec<(Result<Infallible, _>, _)> = Vec::new();
let mut pending_monitor_events = self.chain_monitor.release_pending_monitor_events();
let has_pending_monitor_events = !pending_monitor_events.is_empty();
if pending_monitor_events.is_empty() {
return NotifyOption::SkipPersistNoEvents;
}
let mut needs_persist = true;
for (funding_outpoint, channel_id, mut monitor_events, counterparty_node_id) in
pending_monitor_events.drain(..)
{
Expand Down Expand Up @@ -13131,7 +13165,7 @@ This indicates a bug inside LDK. Please report this error at https://github.com/
}
},
MonitorEvent::Completed { channel_id, monitor_update_id, .. } => {
self.channel_monitor_updated(
needs_persist = self.channel_monitor_updated(
&channel_id,
Some(monitor_update_id),
&counterparty_node_id,
Expand All @@ -13145,7 +13179,11 @@ This indicates a bug inside LDK. Please report this error at https://github.com/
let _ = self.handle_error(err, counterparty_node_id);
}

has_pending_monitor_events
if needs_persist {
NotifyOption::DoPersist
} else {
NotifyOption::SkipPersistHandleEvents
}
}

fn handle_holding_cell_free_result(&self, result: FreeHoldingCellsResult) {
Expand Down Expand Up @@ -15171,8 +15209,6 @@ impl<
fn get_and_clear_pending_msg_events(&self) -> Vec<MessageSendEvent> {
let events = RefCell::new(Vec::new());
PersistenceNotifierGuard::optionally_notify(self, || {
let mut result = NotifyOption::SkipPersistNoEvents;

// This method is quite performance-sensitive. Not only is it called very often, but it
// *is* the critical path between generating a message for a peer and giving it to the
// `PeerManager` to send. Thus, we should avoid adding any more logic here than we
Expand All @@ -15181,9 +15217,7 @@ impl<

// TODO: This behavior should be documented. It's unintuitive that we query
// ChannelMonitors when clearing other events.
if self.process_pending_monitor_events() {
result = NotifyOption::DoPersist;
}
let mut result = self.process_pending_monitor_events();

if self.maybe_generate_initial_closing_signed() {
result = NotifyOption::DoPersist;
Expand Down
Loading